An experimental agent reduced swelling episodes markedly in patients with hereditary angioedema, according to results from a phase 2 randomized, dose-ranging, placebo-controlled trial.
The drug BCX7353, developed by BioCryst Pharmaceuticals, is taken orally and works by inhibiting plasma kallikrein, an enzyme overexpressed in hereditary angioedema, a rare genetic disease that causes severe tissue swelling. In research published July 26 in the New England Journal of Medicine (N Engl J Med. 2018;379:352-62), Emel Aygören-Pürsün, MD, of Goethe University in Frankfurt, Germany, and colleagues, randomized 77 patients with type 1 or II hereditary angioedema and a pattern of frequent attacks to one of four doses of daily BCX7353, or placebo, for 28 days.
Dr. Aygören-Pürsün’s group found significant reductions in the number of monthly attacks for the three doses used in the study, with the best response seen in the group receiving the second-lowest dose of 125 mg. These patients saw a reduction of 73.8% (P less than .001) in monthly attacks from baseline, and 43% of patients receiving that dose had no attacks during the study period. The higher-dose groups saw more adverse events and apparently less efficacy, with the 250-mg dose associated with a reduction in attacks of 44.6% (P = .01), and for the 350-mg group, a 45.5% reduction (P = .006).
Patients receiving the lowest dose in the study, 62.5 mg, saw a small (about 10%) reduction in attacks that did not reach statistical significance. Gastrointestinal adverse events were reported in the two highest dose groups, and three patients in the 350-mg group dropped out after reporting serious adverse events, including one liver disorder considered likely related to the trial regimen.
The efficacy of the highest doses “was probably masked by gastrointestinal adverse events that may have been misattributed as early symptoms of abdominal angioedema attacks,” the investigators wrote in their analysis. Improvements in angioedema-related quality of life scores, a secondary trial endpoint, reached statistical significance for the 125- and 250-mg doses.
The authors cautioned that the safety of long-term dosing would need to be studied in longer-term trials.
The study was sponsored by the drug manufacturer, BioCryst Pharmaceuticals. All of the study’s authors, including the lead author, disclosed financial relationships in the form of grant support, fees, or employment with the study sponsor.
SOURCE: Aygören-Pürsün et al. N Engl J Med. 2018;379:352-62.